There is a wide variety of heroes in Overwatch, and their differences are not limited to their appearance. Some characters are very demanding on the player's skills, so it's better to start getting to know the game with the “simpler” characters. In my opinion, Soldier-76 and Lucio are great for this. Both are fairly easy to learn, heal yourself and your allies, and will bring a lot of benefits to the team even in the hands of a beginner.
However, I highly recommend playing with all characters. Not necessarily a lot, a few Quick Matches should be enough to get you started. Firstly, this way you can choose a character to your liking. It doesn't matter if you enjoy shooting from afar, swooping in or helping your allies, there is a hero for every taste in Overwatch. Secondly, you will learn from your own experience what a particular character is capable of and how to better cope with it.
To quickly upgrade your account, you should use a boost. But be careful here. Boosting accounts in Overwath is a prohibited technique, so you can get an unlimited account ban for it. If you nevertheless decided to pump a high rating for your account in the competitions of the current season, then contact the professionals. Now there are many sites on the network that provide account boost services. Despite the fact that boosters promise fast and safe rating leveling, be careful, because they often steal personal data, change profile settings and steal game accounts. Collaborate with the best companies like https://overboost.pro/overwatch-boosting and have fun with the gameplay