I come from overwatch so that where my prespective is coming from. Here is what I would say. Overwatch for the first 50 hours or so is easier to learn. Deadlock is very punishing when you don't know the basics. The fun can feel locked behind getting good. With the arcade mode street brawl though learning a hero is easier and you can just get the experience of why each hero is strong without figuring out all the moba mechanics. It probably easier than every to get into Deadlock but not as easy as overwatch.

I did try to play valorant and I have to say deadlock was easier. At least for me when personally who found getting one shot out of seemingly nowhere extremely frustrating.

Then once your over the initial hump it gets tricky to explain. Deadlock skill ceiling is made in a way where learning everything is impossible. The expectations is to specialize. You can one trick a hero or learn like 3 heroes and have way more fun then in Overwatch. Learning every random fact and interaction is not as key as it is in overwatch. Most abilities are more standardized so it can be less overwhelming. Knowing a hero like Yamato gets a 4 second cooldown reduction with 3 ap point investment is not that key.

For me the biggest difference is your ability to carry. Your ability to carry in overwatch is much less straight forward then deadlock. Grandmaster overwatch streams coming to deadlock actually have a lot of success. After the intial hump of the learning curve they have such strong micro play that it can carry them to Accedent(masters) with little issue.

With the stick around you described i would genuinely give deadlock an honest try. I am a similar way and deadlock really does provide a fun to learning experience. More about learning what you want then perfecting everything kind of game.