Pieter Levels (the guy who made Nomad List) reached $1 000 000 ARR with a single VPS, all his code in an index.php file and using FTP to transfer the latest code to his server...
I think if you’re a solo founder you have to accept on day one you’re at a time disadvantage when it comes to the actual hours you’ll spend on moving the business forward vs admin, ops, legal stuff etc etc and so you have to really fight smart!
I.e K8S? Definitely don’t need it. Complex CI/Deployment workflow? Nope, just the minimal shell scripts to do clean deploys and rollbacks. Pay for a HA RDS so you never need to worry about DB replication etc.
If you just work with the minimal set of tools you’re comfortable with and relentlessly keep things simple it’s possible. I’ve built high availability stuff as a solo founder and still found (at least some...) time to work on sales and the business.