Self hosted on a cloud provider (not AWS). Interestingly when I logged into Microsoft's Smart Network Data Services I could also see my VPS provider had claime

Self hosted on a cloud provider (not AWS). Interestingly when I logged into Microsoft's Smart Network Data Services I could also see my VPS provider had claimed the IP block as well so they were clearly invested in making sure spam was under control. But nope, still not enough for Microsoft. At one point the mail was even getting hard 550 refused. I contacted their support who to their credit replied, but to less of their credit gaslit me and claimed there was no blocking occurring despite me pasting them full error message with all their tracking IDs in it. The next day mail was allowed in again but still ends up in spam.