TBH, the times I've restarted games (I restart them frequently, though I've only restarted ACNH once, before fully finishing the tutorial, on the day after release), I often get that feeling when having to replay a tutorial section. Usually I just push through the tutorial and feel better and more excited afterwards. But sometimes that feeling of, "Oh... right, I've gotta do all THIS again..." can be overwhelming. But, for me, it passes the more I play.
It might help to look at other islands for inspiration. Look at pictures online or check out DAs (I'm guessing you didn't have access to the Dream Suite right away when you started, since it's quite new- maybe remind yourself what else you have that's new? Like, were you able to dive when you first started? If not, it'll be neat to be able to early on- it could really help pay off loans, for instance) and see what kinds of islands you like. Sometimes it can feel overwhelming if you want to make your island cool and you're just starting... but, remember. It gives you more or less a blank state- you can look take inspiration from other islands and start working towards making your islands exactly how you want it right from the start. Pay special attention to things you like you DIDN'T have on your first island- and then work towards them! Your island isn't as fancy as your old island right now... 'cause you just started! But it still has the POTENTIAL to be better than ever, even if there's a bit of a slog at the very beginning.
