Online will always have some amount of lag but most of the time, it's only noticeable to people who are used to precise inputs (not Phil). Though most of the time, its at most a couple of frames (100ths of a second and is assuming a decent connection from both parties) and isn't easily seen by someone who doesn't play the game at a high level or cares for frame data. And when lag gets bad enough to have a noticeable effect, it affects both parties as the data has to be sent to both parties (and thus why lag isn't an issue offline, there is no extra steps outside of the game translating the button press). This is why competitive scenes do want to get back to in person tournaments, as they are autistic enough to care.I know almost nothing about fighting games. Is Phil's claim of online having lag supported in any way? Is there any difference between playing online vs in person? Not asking is he experiences it, asking if it's possible.
When Phil complains about "lag", he's only looking for a convenient excuse to not accept that someone could play a game better than he can. He's used the claim of lag when playing against an offline bot.