My understanding is that for reliable email, you need to host with microsoft or google otherwise you are more likely to get sorted into junk mail.

That’s technically accurate, but it depends on the context. For example, if you set up DMARC properly and use a brand new custom domain as a personal email, yeah, you’re much more likely to get sent to spam, but not necessarily right away, and as you use that more frequently, or communicate with people using the larger providers like Google or Microsoft, the higher the “reputation” of your domain will get.

If you want the highest possible level of reliability though, then yeah, Google or Microsoft’s options are likely gonna give you the highest chance right off the bat without any fuss.