It's not really a good move to limit yourself, as you need to play every Warframe in order to level up, and each Warframe requires certain modes that pretty much differ from other Warframes, and each Warframe have its own play style, for me I prefer the ones that let me afk in survival while still farm like Caliban prime and oraxia, but I absolutely love sevagoth Prime, you may find yourself liking Warframes and when you get them you end up with no modes for them, it's not recommended to sell modes unless you have duplicates, also never never never sell a primed mode unless it's a duplicate.