Yes. You just need to be patient. If you look up some youtube channels that are pure F2P, they're pretty impressive. Your account will naturally grow with great champs over time that are free, either login ones (like Rathalos which I'm hoping you started soon enough to get) and later ones you get from either total days played (like Scyl) and Mithrala/Arbiter from in-game content.

Best thing to do to grow your account is get to where you can clear Ultra Nightmare and Nightmare clan boss each day, that'll get you 10 sacred shards per month on average

I am an end-game player, and for the most part, the only money I spend is the daily gem pack, which is $10/month.  I spend more time playing RAID than I do watching Netflix, so I look at the $10 as a monthly subscription.  

I have been playing since December 2019, and I did spend some cash on energy packs in my first year.  It was the pandemic and I was bored and stuck at home, and there was a lot less free energy back then (No Daily Goodie Bag Pack, No Energy from DT or Sintranos, No Energy from Advanced Quests).

There are a few people in my clan that are totally F2P.  One of them has been playing just as long as me and his account is almost as strong as mine. Another is a newer player (12-18 months) and he is crushing it. 

If you are going to be a low-spender or a F2P player, RAID is completely a game of resource management.  You will need to learn to ignore the FOMO that Plarium works hard to stoke, and stockpile your resources for when they will best help you advance.   

before this reddit repost (https://www.reddit.com/r/RaidShadowLegends/comments/1b6jjov/do_you_believe_this_game_can_be_enjoyed_without/) thread gets slammed with phishing links, gonna lock 'er up.