Just an update, I've had to pause the .Net Core dev for the moment while I deal with changing hosting. I've been with my current company for about 15 years, and until the last year or so, they've been great. However, when I wanted to update to a newer windows server container, their cart failed - a lot - over several months. So I finally took the time to log a ticket, and got back a "we are migrating to a new infrastructure" and could not give me an ETA only to say it would take a while - and then they offered me an AWS Lightsail container... I also could not get them to clarify the backup situation as windows lightsail containers cannot be automatically backed up... Then their marketing site went down for over a week...
I decided to independently test out AWS, got a basic server going & set up for web hosting, but no email... I filled out the form to request opening port 25 and got back a denied and a "we can sell you bulk email delivery" link. My day job pays well, but I'm not paying more than my web hosting (or cable bill!) to use someone else's mail platform. If you just need web server, it would be perfectly fine, but I still self host my mail using SmarterMail - because I can just copy the config over when I need to go to a new host and I'm up and running.
I've used GoDaddy for a long time as a registrar and as a DNS provider. I'd seen they had VPS containers for a while, but never tried them out. So far it's going well, double the RAM, 5x the disk space, same core count as before, but $25/mo less what I was paying. I was able to open inbound port 25 to receive email and point SmarterMail at their mail relay, and it mostly works, however, a lot of mail I've tried to send, which in the past was fine, gets blocked as spam at their relay, to me it's random what they think of as spam... but this is a mostly viable host, I just need better SMTP deliverability. They also do backups, though I can't tell it when to do the daily, but I can schedule a one-off one. They also have an awesome recovery console - web based VNC on localhost - you can even watch it reboot - or fix a bad firewall rule that dumps your RDP connection (oops!).
I considered MailGun, but they canceled my demo without telling me because my volume is "too low" and they wanted me to just do their free trial rather than answer very specific use case questions, then I did some digging and found mention of a few other providers on webhosting talk, so I'm trying out Intertune's Sendmetric - a batch of mail I had tried to send could now send!
We'll see how this goes, but with the GoDaddy price + Sendmetric, I'll still be paying about the same as before, but with a lot more resources.