Yes, you can play solo meaningfully. To what end "meaningfully" is, depends on you.
Most AI in this game are able to be learned and worked around as a solo player. Often this requires unfortunate, sort of immersion breaking, tactics, but it is still doable.
You could roll a full tank fighter and get away with a lot of nonsense, as
@RaptorBlackz mentioned. You could also run a Mounted Archer build to be able to do most content alone. I personally play a full human with a complicated hybrid build - it enables me to get away with a LOT as a solo player, but the costs can be high when I make a mistake.
So, the particular build would depend a lot on what you want to accomplish. A tanky MA would be the hands-down most self sufficient class, but you will lack versatility (and speed) on foot. If you are okay with that, try it out.
In the end though, it's a 'learn to play' sort of issue. Most people would never dream of fighting Sators or other PvE content with a full human in light armor, but, I do it anyway (and succeed a lot!). So my final suggestion would be to evaluate what specifically you want from the game, how you could approach that content, how effecient you want to be vs having fun or being immersed, and then ultimately choose for yourself.
