The biggest change imo is that the "use a servant's cards as a star generator" meta from the start of the game has somewhat ended and been replaced with more and more servants and CEs with passive star generation. The old system needed you to use a low damage servants cards to generate tons of stars in exchange for reduced damage, then hope that your damage dealer actually had cards come up the following turn in order to make good use of the stars. If your damage dealers cards came up when you didnt have stars ready, or you had stars ready but with no damge cards, the teams damage output was pretty lackluster. Being able to count on a certain number of stars every single turn, or at least for 3 consecutive turns makes for a much better team.
Fragments of 2030 is the premire crit team CE, giving you 8 stars every turn and it can be stuck on anyone. His Rightful Place (from the Fate Zero event) is a good f2p alternative offering 4 stars per turn instead. Other CE options exist as well for passive star generation, Moon Bath is one I believe.
Servants likewise have skills that will guarantee stars per turn. Hans and Halloween Elizabeth have Innocent Monster which gives stars per turn for 3 turns, and both are f2p friendly. Some others like Summer Marie, Merlin (on his NP), Saber Lancelot, Jeanne, Amakusa, etc also have skills that offer 3 turns of guaranteed stars per turn and could be brought as supports.
There are also CEs or servant skills that offer a big dump of stars all at once. These can be used with Plug Suit Mystic code to switch them in on a turn when your damage dealer has all of their cards available for a hard hitting brave chain to basically guarantee them a crit filled brave chain.