3DS sold >3.5M in 2018, >1.5M in 2019 and so far 378K in 2020. In 2017 it sold 5.8M post Switch-launch. So it sold >11M after the Switch launch. I doubt anything else comes close.
PS3 sold 8.19m post successor, and PS4 is still selling more than it launch aligned.
PS3 Jan - Oct 2013 = 5,953,251
PS4 Jan - Oct 2020 = 7,597,738
PS4 is also seemingly getting better support, PS3's last major 1st party title was DEC 2013 with GT6. PS4 is getting Horizon 2 next year and just got a major title in Miles Morales, and a lesser one in sackboy.
3DS sold 11.3m post successor, PS4 might not beat it but it will easily come close.
If PS4 got an official price cut it would breeze past the 11.3m, but I doubt that is going to happen so it will be a much tighter race.