FIRE [17-001H] Adelard The damage dealt...cannot be reduced means that effects such as Reduce damage and Change damage to 0 are ignored, and the original damage is dealt
My final recommendation isnt even a Human at all: Shabraz, the Skyshark
You can cast it on turn five with no acceleration, and then swing for 10/10 the next turn after activating with mana-making effects you often find in these decks like Chromatic Lantern, Command Tower, and City of Brass
If it's granted double strike, then it'll get two such counters if it can hit a player, making it grow quickly
Warhammer 40,000: Commander Decks come out on August 12th, 2022
Especially with an increase in 3 color decks getting played, the targets you have seem to have reduced significantly over the years