Roger Federer seems on a permanent swoop through the tennis firmament, dipping and soaring like an ageless Alpine swift, held aloft on the breeze forever. He says his journey might yet end in Tokyo, at the 2020 Olympics, although he is promising nothing.

This week the 36-year-old Swiss descends on Rotterdam and, if he wins three matches (he has lost only six in 29 here) he will return to No 1 in the world, taking the crown from Rafael Nadal, at least for a while.

Contrary to interpretations, Federer has had in the back of his mind since November that this ATP 500 tournament would provide him with a rare chance to get back to where he has previously ruled for 302 weeks, more than anyone in the history of the rankings. The last time he was king, in November 2012, he had beaten Andy Murray four months earlier to win Wimbledon. This week Murray, still recuperating from hip surgery, slipped out of the top 20.

Federer’s opponent in the opening round in Rotterdam will be the Belgian Ruben Bemelman. They have not played before and probably will not play again. If the Swiss reaches Friday’s quarter-finals, he could meet his compatriot Stan Wawrinka. The winner will probably face Philipp Kohlschreiber or Karen Khachanov.

When Federer arrived late on Sunday night, he went straight to the practice court with his coach, Ivan Ljubicic, and his fitness coordinator, Pierre Paganini. In 2005 Federer beat Ljubicic here in the final. His other Rotterdam title arrived in 2012, when he saw off Juan Martín del Potro. On his last visit, five years ago, he lost against Julian Benneteau in the quarter-finals.

In a long, discursive interview on Monday with the Guardian and the Dutch newspaper NRC Handelsblad Federer revealed what is left of a career that has already yielded 20 majors and how he has controlled his destiny through meticulous planning – as well as daring to experiment. Paramount, though, is family, health and happiness. He is among the most famous people in the world, yet he glides in and out of the spotlight with comfort. “Ever since my kids were born it has been that way. My wife needs to be happy. My kids need to be happy. Without that this doesn’t matter.”

Does celebrity not weigh him down? “I’ve got a very busy and exciting life. I get to meet a lot of people. When I don’t want to meet people, don’t want to play tournaments, I can choose to do that. Since 10 years now there are mobile phones to take videos and pictures. You do feel like maybe your privacy has been taken away even more. But it’s OK. I don’t feel like it’s too much and that I can’t take it. You think twice when you go out sometimes. You think, am I in the mood for maybe it to happen, or am I just happy to stay home anyway? I try to just have a normal life, go for a walk, see my friends...”

I’m not just going to play tournaments to see how I’m feeling Roger Federer

So, would he aim at the Olympics, where he has yet to win a gold medal in singles, one of the few baubles to elude him? “It’s not like with Rio [in 2016], where it was really something I set myself as a goal,” he said.

“If I’m still playing, great. But I’m not saying I have to play one more [Olympics] before I retire. If it happens, then it makes sense for me to go play, but it’s too far away. I don’t know what happens then. We’ll see if it works and makes sense. I haven’t put it on the table. It’s not a discussion point, let’s put it that way. When the time is right, I’ll talk about it – and see how I feel in that year. When is it? 2020? It’s so far away. There’s no point to discuss it. Why not – it would be nice ... but I can’t tell you for sure, or not for sure.”

Tantalising, as ever.

As well as being the greatest tennis player of all – according to Rod Laver, whose own claim to that accolade is considerable – Federer also has a command of his time and space, on and off the court, like no other. Is there a secret to the longevity of his career? He does not see it that way.

Federer celebrates winning the Australian Open last month. Photograph: Julian Smith/EPA

“You can always play more if you want to. You can always play less if you want to. I just hope people don’t think that what I’m doing at 36 they can start doing at 25. I played full schedule from ’98 or ’99, really, to 2016. Until I was injured. I was 34 at the time. Did I plan last year to play a light schedule? No. Did I plan to skip the clay-court season? No. Did I plan to win all these tournaments? No. It all happened organically.

“I played [three] majors [in 2017]. I won two of them. One of them [Australia] almost killed me by playing three five-setters. I was injured afterwards. Then I also couldn’t play. My philosophy is I play when I’m ready. I’m not just going to play tournaments to see how I’m feeling. What I did last year – and what Rafa [Nadal] is doing also – is maybe a bit of a lighter schedule, and it shows to others by working or practising a bit more – or taking time – you can improve your potential and you become a different or better player.

“Say I go out for six months and I only work on my serve-and-volley game. I feel like I’d be a different player six months later but everybody’s scared to do it because they’re, like, what about my ranking, what about this, what about that? Sponsors maybe, or prize money, I’m not going to make money. It’s hard to say. I just won’t do it, right?

“I hope I take that fear away a little bit, that sometimes it’s OK to take time. That would be a wish for me: that players would read something into that – not that they just start doing it because the top guys are doing it. We’re doing it because we’re older and we have thousands of matches in our bodies. That’s why we have to do it this way.”

Would he play Roland Garros, which he skipped last year, along with the rest of the clay season? “I would like to play everything. No, honestly. But it’s impossible... So, unfortunately I have to start taking things that helped me at my [time of] life with my family. That’s the priority. Then comes my body and my game and everything. What can I do? What’s too much?

“I guess by being here now, and maybe being in Dubai, it’s just going to have to be lighter if I play the clay-court season. Or not at all. So I just have to get into this situation a little bit, because the priority is for me to try to defend my sunshine double in Indian Wells and Miami. So, then we’ll see what happens with the clay, what happens next.”

What happens next? As opponents know on court, that is the impossible conundrum with Roger Federer, the elegant Alpine swift.