[Nican]

I just have an old Dell computer [1]. They are pretty small, quiet, has an SSD, and I do not need to fiddle in having everything compiled for Arm.

I would also put your app behind CloudFlare.

Also- if you are able to afford an intel NUC ($200?), and the app is low resources enough to be able to run on a Pi. You could also consider getting a VPS ($10/month).

[1] Something like https://www.newegg.com/dell-optiplex-7090-business-desktops-... - but older, and found on a local recycling center.