So Samurott only resets debuffs once at 50% time remaining, which is perfect for the usual Azumarill solo clear strategy.
I did actually take a death here, and I will give most of the credit to the supportive AI I retained from the last time I played an Eevee raid online, with Drifblim burning and Arcanine adding Intimidate and Leer support. Otherwise this is pretty much the typical max HP/Atk Shell Bell Tera Fairy Azumarill set with Mud-Slap/Belly Drum/Play Rough, in a very adlibbed fight where I was still trying to get a feel for how much I could set up. I settled on Tickle as my 4th debuff slot since Arcanine had Intimidate handled but I wonder if Charm or Chilling Water could be even faster, or Defense Curl to recover from defense drops. Razor Shell defense drops were annoying, but I did take an acceptable death here anyway after terastallizing (Fairy tera) to break through the shield, which also restores Azumarill's resistances to every move, which is appreciated to lower the danger of Razor Shell but is still a necessary risk to take to break through the shield as a Fairy tera. I was considering Clear Amulet, but you really do need to be self sufficient with healing to get the last Belly Drum in.
In this attempt I ended up using Tickle T1, getting a Razor Shell defense drop but keeping the attempt going because of an early burn. Then I just went for getting 2 more Tickles in before the shield went up and then going for 3 Mud-Slaps to tera. I used my last heal cheers with min rolls of 80 to get enough HP to Belly Drum, while I still needed to dodge multiple hits to survive.
With Samurott at -3, Belly Drum barely didn't break the shield in one hit but I healed up to 299 HP, which also triggered the last buff reset for our side. I decided just to hit again to break the shield since Samurott was about to reset its own stats, and I got 1 Mud-Slap on the free turn after the break and died, though Drifblim fortunately reset burn again before Clodsire could poison.
After respawning, I set 1 Tickle back, then went for 2 more Mud-Slaps which sent it to 50% HP to Focus Energy. I took a few more Razor Shells but avoided the defense drops, taking me down to 51 HP and forcing me to go for unboosted Shell Bell Play Roughs to heal enough to Belly Drum while Samurott was at about -2 from Leer, which I was healing 50 damage from and managed to get back to the 50% range with fortunate misses.
In the end I used Belly Drum and landed the last 2 Play Roughs to finish in the nick of time. Samurott landed its last Razor Shell on me but it was too late.
Overall I would say Azumarill probably makes for a great support in my experience and I am interested to try it in the online circuit.