Worn out chainring or missing tension
I will focus on the chain tension part of the answer, as your big chainring is clearly worn out. However, do note that increasing the derailleur spring tension wouldn’t stop the chain skipping on the worn chainring. Therefore, this answer is mainly for the sake of interest.
By chain tension, I believe you actually mean the tension in the rear derailleur spring. This spring takes up slack in the chain. If your spring tension were too low, the chain could be slack in some or many gears. However, I don’t believe that it’s a setting most users need to manually change, as the factory tension is likely sufficient. From this Park Tools page on overhauling rear derailleurs, Shimano and Campagnolo RDs appear to have one setting for increasing the cage tension from the stock setting. SRAM appear to have one setting higher and one lower. I actually don’t know of any clear reasons you would want to increase the cage tension, but it is possible to do so. I suppose that if you were converting to 1x without a clutch equipped RD, you might consider increasing the cage tension, as discussed in this previous Q&amp;A. (If you do this, you might consider using a chain guide as well.)
Less relevant to you, I recall that Friction Facts, an independent researcher later bought by Ceramicspeed, showed that all else equal, higher cage tension meant slightly more drivetrain friction, although manufacturers objected that the cage tension was necessary to ensure good shifting. I believe that Ceramicspeed’s oversized pulley cages contain at least one position which lowers the cage tension from the stock Shimano or Campagnolo setting. The amount of drivetrain friction at stake is quite small, likely considerably less than 1W.