[machiaweliczny]

Try „Les Mills bodycombat”. I am pretty fit and have trouble with medium level. Best cardio on VR.

For more fun „Pistol Whip”, also great

[traverseda]

I'd say that's more of a rhythm game than a boxing game. There are a fair number of entries in that genre, beat saber is popular, supernatural is similar.

Honestly though you can just search for "best VR workout games".