Thanks for the interest in the game!
In my own playtesting and the playtesting feedback I've received overall, I haven't found that to be the case (with the most recent version of the game, at least), but your mileage may vary. This is a game building on OSR-style, player-driven roleplay so your character sheet isn't necessary a guide to who you are and all you can do as much as it is a toolkit for your character to use. In playtest, I've seen a huge swath of memorable and fun characters, seem folks go all in on Health and Armor to great effect, all in on Speed to powerful but fragile results, and seems people multi-class and go all in on unique conditional abilities as well. It's not perfect yet, of course, but I have rarely encountered someone going all in on Speed and feeling uniquely overpowered.
The most recent version of the game did tweak Backstabs, making them less powerful than in the original early access launch version. That said, positioning and backstabbing are intended to be powerful tools in this system but focusing on Speed as you advance means sacrificing Health so you tend to become a glass cannon. Great when it works out, but it can be scary when it doesn't (and things start to get weirder and more uncertain as you face off against more and more corrupted foes).
If you are looking for something with the tactical consideration of say something like Descent (the board game) or lots of layers of complexity like Pathfinder 2e, this game is definitely not that. Tacticians is mean to speed up and streamline DnD-style tactical combat to retain the fun combos and dramatic moments without slowing things down by giving you a massive character sheet, lots of die rolls, etc. So some depth is definitely sacrificed as part of that trade-off.
That said, I never want to pressure anyone to spending $$$ they are unsure about. The game is going to continue to grow and develop in the months to come so there will be more options, further tweaks from further play testing, etc.
I hope that helps!