If you use Obtainium to download apps from Github etc., you are vulnerable in principle to downloading apks specially crafted for you by MS and the like.
The best way to avoid this is to use a Tor proxy.
How to use a Tor proxy with Obtainium? I already have a VPN, so I can't set up Orbot as a VPN. But I can use Orbot as an http or socks proxy. Does Obtainium support connecting through a proxy?