Sure would be. Main problem we have in a siege is having to rotate our troops to maintain the pressure 24-7 with absolutely no letup.
However, in 2019 I was part of the outside relief crew in defending the Embassy of Venezuala from a nearly month-long siege by wealty ex-pats supporting a Trump-inspired coup attempt. The Embassy staff had been PNG'ed, and on the way out they gave the keys to Code Pink and Popular Resistance. Initiially things were chill, but once the coup attempt went down fighting came to the Embassy and the siege began in earnest. The heavy stuff lasted about two weeks. It took not one but TWO tries for police raids to dislodge the defenders. Remember, most embassies are in fact capable of being defended as fortifications in an emergency.
We found ways to resupply. These upscale exiles (some of whom we had on video shopping at Georgetown's most expensive stores) had little experience running a siege. They were always there but would quickly take any bait we offered. We would make a show of a frontal attack to get a single bag of food inside, and ALL of the beseigers would come around to the front. While they did, three whole carloads of food went in the back. This worked SEVERAL times.