And that is no different from any other game that has progression systems. Progression eventually gets slower, the initial rewards get left behind after their initial bounty. If you don’t play as much then you don’t progress as quickly.
However because this system is randomised actually there is a case that overall those people who play lots more than you won’t progress as quickly past your level. Then throw in match making considerations for star card levels and such and you’re definitely entering a realm where this game gives a more likely balanced encounter for you as a less frequent player than others where there are no microtransactions involved.
In fact in the same breath as all these complaints you will have gamers, maybe some of the same, maybe a different portion, who complain when there isn’t anything to work towards. The bizarre state of our community and the tightrope devs have to walk.