There are some big third party switch 1 games/ports that are currently having issues running on Switch 2. Just to name a few with 'startup issues' that I personally loved playing on my Switch 1:
Doom Eternal, Wolfenstein 2, Rocket League, PizzaTower, Warframe, Multiple Jackbox titles.
I really hope that the 'we are investigating the issue' implies that these issues will be resolved before June 5 because these would be big ommissions to me.
by gio458