New players should be able to get a free champion
Once a player reaches level 20 or 25, I say they should receive a free champion. It's incredibly hard to grind out IP for champions that you want to play, especially since everything is soon going to be multiplied by 6.5x. This should be done in accordance with the leveling rewards. By the time they are level 20 or 25, they will already have probably tried multiple champions on free rotation and see which ones they like best. They will probably have already seen every champion in game and see which one they want to play or are interested in. Having to grind for it as a new player kind of sucks though since playing games will seem more like a chore than actually having fun.
The players will not be asked to pick a champion right when they hit 20 or 25, but instead they should receive a free champion voucher that they can use in the shop. This way, they won't be pressured to make an instant decision since some people take more time than others to decide on one champion.
Questions I know will be asked: "But won't they just pick a 6300 IP champ" First off, if they're really a noob, then I say at least half of them won't and half of them will pick a champ they have a genuinely fun time with. If someone is making a new one trick account for ex. a one trick kindred, then this helps them too.
"Riot will lose a lot of money from the champions that could've been bought" It should be common sense not to buy champions with RP if you can just grind it out instead and save $5 or $10. If new players do want to buy champions with RP, then they will learn soon enough that wasting RP on champions sucks since you can use it to buy skins instead, which can ONLY be bought for RP.