I‘ve been doing exactly that for roughly 10 years and never had a problem with Gmail. You just have to set everything up to latest best practices (DKIM etc.). I‘ve even changed IP addresses a couple of times.
I self-host for 20+ years, the last 12 years on Hetzner. Did some transactional mailings as well professionally. Not spam, but forum notifications, mailing lists.
2007..2014 were probably the worst. Gmail was chainging often, Microsoft was blocking everyone.
I think self-hosting is easier now than 10 years ago.
I self-host on Linode, and they occasionally fall into UCEPROTECT level 3 (the ISP-wide blocklist), likely due to a spammer trying to set up business as a Linode client. You can't really do much about ISP-wide blocklists, and honestly mail servers should not aggressively reject E-mail simply because some other rando at the ISP sends spam. I've always had success working with the aggressive mail server admin to get unblocked. Often it's just an E-mail to provider-abuse@provider.com
They come across as pretty scummy: "Yea, we put your whole VPS provider in our blocklist. It's their fault for having one spammer customer: Blame them! By the way there's nothing you can do about it--except of course pay us to be whitelisted..."
I run two different private email servers, both set up pretty much identically with all the modern "best practices" as you say. One of them is on an address that has been stable for the past 10 years, and on a quality ISP that actually cares about reputation, and mail delivery is mostly not a problem. The other one is on a cheapo ISP, and mail delivery is so poor due to neighboring IP addresses causing me to get block that I gave up and resorted to using a free SendGrid account to relay my outgoing mail through.
