IP blocklisting is still very much a thing as well so you can expect any mail originating from a residential IP to be rejected due to their /24 or larger having previously sent spam, and that assumes you can send server-to-server mail (destination port 25/tcp) in the first place since many ISPs and server providers block traffic destined to that port by default to prevent users from getting their IP blocklists. My home ISP blocks outbound SNMP traffic (or at least did 10 years ago) presumably to also prevent abuse. That said, things like blocking inbound port 80/tcp and 443/tcp is purely a measure to prevent people running servers at home which I’m not a fan of.