The risk benefit here is clear. Omicron is so mild many don’t know they have it. The most that a booster (of wrong variant btw) will do for you is lessen the viral load when you get infected but this benefit will fade. The mRNA vaccines contain actual COVID virus with two gene splices in the spike, but these do not alter the properties at the tips which I understand are involved in the blood vessel lining irritation and capillary clamp down them micro coagulation. If you are unlucky and the booster hits a blood vessel this is known to irritate the entire vascular system and heart. Your doctor can be partly forgiven as they are under pressure to repeat mantra. But I would not forgive that doctor as he has an obligation to inform himself. Still, if you must get boosted make sure you have your living will set up and so on. Also ask your Doctor about ACE meds on top of blood thinners (if these might help). The idea being that the ACE med might lessen the capillary clamping and the thinners (you are probably already taking) help reduce the powerful clotting induced by the vaccine. Maybe show this note to your doctor and pay attention to his reaction? Ask yourself if his reaction is consistent with a physician you want looking after you. Please let us know how this all plays out.
On my side I am waiting for my MRI to get a sense of my future. I might have nothing serious or opposite.