Worked at the USMS HQ as a lowly guy in the congressional and public affairs office for a bit back in the day. Full blown white collar shit, but I did have some pretty cool experiences getting to know all the different corners of the Service.
Most likely if Marshals are going to execute a warrant on 1600 Penn it will be through communications channels first to try and work out a discreet transfer out of public view with minimal fuss and muss. Then send a couple of guys physically to serve ask him to remand himself, out of SOP. Probably if they have to go ask under congressional mandate, where POTUS has been non-compliant and they know it's if at least in image a shoving match, I would think they'll send another couple guys in to ask nice again, with a team or teams from the USMS Special Operations group in Louisiana staged nearby on standby if they need a show of force. Or need actual force.
Most likely all the extremely hardcore defenses are against assault on the perimeter. For example there are probably no pintles and concrete hardpoints inside the building.
If they let the Marshals warrant team and their tactical Special Operations backup inside the perimeter during the initial final last nice ask, thinking that it's just a show of force that they're going to turn away easily. Then that makes the job a lot easier but still not easy.
Then it actually becomes a gunfight crew against crew. Problem is it's always harder to be the assaulter versus the defender in a situation where you have a place that is prepared and trained for potential assault.
Unless there is an outrageous overmatch in manpower and skills, and it's able to be employed from multiple angles of entry, I see it as a losing equation for the assaulting Marshals even if they have a team of former tier 1 guys.
Assault, assaulters lose or pay an extremely heavy price. This is one where you besiege in place and use attrition. With congressional mandate, all you have to do is wait it out. With Congress and the majority of the public against the president, eventually the tide will turn, especially as Congress puts the VP in the top slot due to the situation and then technically primary secret service allegiance would stop being to Trump.
I think regular line secret service has a ton of ex cops, and ex regular line Mil.. and maybe a few guys sprinkled in from the Agency, bureau HRT, and SO, but other than the size limited SS tactical team on standby, I don't think the defending secret service force on premises is possessing of any super-powered skill beyond any other similarly composed force of mostly ex civilian law enforcement.
What they will possess, is training, procedures, and equipment to defend the specific premises you are assaulting. Hence the need for a really big over match in multiple dimensions unless you want a huge blood bath youre on the losing end of.