Alan Webb would probably come closest, I can see him getting 10.80 from a sprinters start with no blocks. If you gave Saruni some time I think he could get somewhere around 13:45 and 10.70, Brazier somewhere around 13:50 and 10.90, a prime Makhloufi maybe 10.75 and 13:45, Rudisha 10.90 and 13:45, Coe 10.95 and 13:50, Kerr 10.80 and his 13:23 PB, Centro would probably break 11 at his best, I'll give him 10.95. Korir should be the obvious choice but when you look at the way he runs his 400m races, he's more at the bottom of the list. Always uses his 800m strength to his advantage in the final 65 metres. Given the same conditions as the rest of the athletes I named, he could run 10.65 maybe, considerably ahead, but would probably run 13:50 in the 5K all the same. A prime Augustine Choge could run a 10.85. According to some YouTube channel Hocker closed his final 100m in 11.14 in NCAA indoors but that's obviously fake, still giving him the nod for sub 11. A bit surprised that Timothy Cheruiyot isn't in this conversation. I would have thought some idiot would bring up the fact that he went out in 52 and still ran 3:28 last year, but I'm pleased that he's not being talked about. He'd be lucky to break 11.35. He's still got more speed than Jakob though, I'll give him that. Jakob can run 11.8. Ovett's form immediately says no to sub 11, but not in such an extreme way like Jakob Ingebrigtsen, he could go 11.05-11.1 at his prime. Hicham El Guerrouj should be able to run 10.75 so maybe he's the best male 100/5000 runner of all? Lagat wouldn't be too far behind, should run 10.90. Morceli ran his 1:44.7 800m best at 21, 4 years before his prime so I'm guessing he could get 10.90-10.95. 2020 Wightman could go 11.20 and 13:50. Elliot Giles can run sub 11, 10.85, but his aerobic endurance needs some work to get sub 13:30, and combine that with rather stiff form and you'll probably get a 13:55 from him. Longest distance Lewandowski has raced is 2K and he was fine at that, ran 4:57. With a year of work, I can actually see him getting close to 13:30, but he can probably run only 11 flat in the 100. The other Pole, Adam Kzcshot, has really great speed - in the latter stages of a fast 800m race, only showing his extroadinary anaerobic/aerobic conditioning. 11.15 and 13:50 for him. So yeah, I'm done.
TL;DR: no one.