Step 1, I'd move off Linode. Find a local DC or business you can support by hosting a VPS or dedi box with them. LowEndBox might be an interesting place to search but avoid anything too famous.
Step 2, join this https://sendersupport.olc.protection.outlook.com/pm/services.... They don't actually email me when they block my IP, but at least when I contact them I can argue I'm already in their program and they didn't actually notify me of any sending issues. I've got myself unblocked relatively quickly this way.