Sorry - my reply won't be really helpful to you, but I still want to say it because I think I have a bit different perspective on that problem and maybe that will be of use to someone.

I actually use that "forgot for half a year" approach to "curate" my wishlist. I usually aggresively wishlist a bunch of games during game events and so on, and then, about once a year I return to my wishlist and ask myself, if I still remember what were in those games that caught my eye, are they still interesting to me? If I do not, and looking at trailer and/or screenshots does not hype me up again, then it does not worth spending on (at least right now). Then I remove those that I decided to not play at all from the wishlist.

I use GGapp.io to track my video game stuff. They have a wishlist feature and iirc you can add notes to the page. Doesn't track prices though.

GGApp.io

I use LibreOffice's Calc for tracking stuff.

...yes, adding data is a chore. But at least I don't have a limit on platforms to add.

https://steamdb.info/extension/

I use steam DB to track my wish list prices. But I genuinely forget why I wish listed something. I just assume if it's on my wish list and the price is low enough I'll just buy it. And figure it out. I typically buy games around $5. So at that point I'm willing to take a risk on forgetfulness.

But I'd say for most games I remember why I found it interesting. Sometimes I have no clue. It's just part of the adventure

I can't help you with this, as I just logged in to IsThereAnyDeal to check if they had a way to add notes to a wishlisted item and it seems they don't.

BUT, thank you for making this post because it turned out Aven Colony was on sale for £3.19 and I must have missed their email!