What I do is take my yearly donation budget and divide it up to all of the projects (don’t forget about those libraries, dependencies, etc)

I would use https://www.taggun.io/ API for the invoice and receipt OCR.

Cloudflare (custom domain)

NextDNS

Zoho mail (you@customdomain.com)

Basic auth over https is encrypted.

Check out Domoticz

Domoticz for home automation

cloudflared for remote access

apcupsd for UPS automation

OpenWrt on x86/64. Also being Linux based you gain features such as SQM which is a game changer for bufferbloat and responsiveness with devices.