You are correct that you cant have everything. You have to choose either speed, or tankyness, or healing in this game. The faster you are the squishier you’ll get, and vice versa.
Like above said, if you are looking at a fast healer the best race is Alvarins (31 year old). They are the fastest race on foot and all their clades are for running and kiting. Their draw back is that they are squishy. They have low hp and, especially if specced as mages, cant wear much armor. For solo player i would recommend them for sure. However, coming from a Thirsar you’ll have to adjust to how much squishier Alvarins are. If they catch you, you’ll die a lot faster.
Humans are only average speed( same as Thursars) , but they can wear more armor as mages, and have more mana regen than Alvarins. Humans really only shine in group settings, imo, with their clade that halves friendly damage. The problem with humans is that they are average at everything. Average speed. Average armor weight. Average melee damage bonus. Average magic damage. They excel at being jack of all trades, but arent particularly strong at anything.
Ps: it is unclear if you are planning to be a melee fighter or dagger mage, bit both races can be either. However, if you want to be a melee fighter you wont have much healing. The only way to effectively heal your mount (even while riding) is if you are a mage, otherwise you have to dismount and use bandages.
There is an Arcane Archer build that is strictly a mounted build (fat wheelchair build) that is a Mounted Archer with almost full magery for healing. While this build is very good for solo mounted farming and surviving mounted fights, once you get dismounted, or lose your horse, you are dead. No foot skills and slow af.