Is 10 man harder than 25 man or am I just bad

A group of friends (some of whom have never played WoW) thought it would be fun to roll on Frostmourne this season and do some 10 man naxx. After 3 weeks or so of raiding once night a week for 3 hours (definitely a small amount of time), we've hit a bit of a wall. We are all 3500-3800 gearscore with enchants/gems. But we have a really tough time getting through fights. the rain of fire on faerlina ticks for like 50% hp within a half second of starting, and other mechanics just seem to kill us too often. All it takes is one of our less experienced people dying and all of a sudden the remaining 9 can't clear the fight. (our average dps is around 3k).

We've all become a little disheartended because we just want to clear the content to some degree without having to commit super hard. And it's only gotten worse because some of us have pugged 25 man naxx and noticed its WAY easier, at least from an individual perspective. Mechanics don't hit single players nearly as hard, so there is time to heal them or for them to take a pot/lock cookie. And if 1 or 2 people die, the boss is still very clearable by the remaining players.

I know this server is tuned up, but my friends and I figure if we can't clear 10 man Naxx, then we have basically no hope of clearing 10 man Ulduar.

Addittionally, we have a resto sham and resto druid 2 healing, and they really struggle depending on the fight (faerlina is stressful, and patchwerk obviously needs 3 healers, with the resto druid swapping to a priest alt just for that fight).

Are we just ****? Or is 10 man really ****in hard despite giving only 200 item level gear.

3k average dps in 3.5-3.8 gear seems awful low. Do you have a good combination of classes in raid group? If melee heavy group it's recommended to have a melee haste buff and for caster heavy groups moonkin gives good buffs via hit, spell dmg and crit buffs.

Shaman + druid healer combo should be viable. Just make sure shaman is tank healing while druid focus more on raid. And dont stay on that rain of fire.

Ulduar 10 will be much harder than naxx and it's recommended to have Naxx gear when doing it.