Yes, you could. The most math you ever have to do is divide by 2, add 3. It’s time consuming but it’s not difficult. The hardest part (which DDB can help with even if you’re NOT using the character sheet) is just searching for lists of valid options (i.e. a list of spells you are eligible for, a list of feats, etc.)

Creature types. Not just in reaction to the 2025 Monster Manual. I consider this a GM-facing rule, subject to by interpretation. So when a Paladin uses Divine Sense, or a Ranger uses a similar ability, or a Cleric uses Detect Evil and Good, etc., or a Ranger has a Favored Foe, or a Druid casts Speak with Animals, etc. - it’s up to me whether a creature counts as a Beast, or Evil, or extraplanar, or whatever. I go by the flavor that the design is going for, and I allow creatures two fall into more than one bucket. A dragonborn might count for some things that only apply to dragons; a fairy dragon counts as a fey and a dragon; a beholder zombie might count as undead or aberration or both depending on what the feature is trying to accomplish; a Warforged might be humanoid and construct; etc.

Readying an action costs one action and your reaction. (There are other costs, too, though, like the fact that you can’t ready some combinations of multiple attacks and bonuses that only work on your turn, or the risk of spending a spell slot without a benefit, etc.). Either way, your point definitely still stands.

There’s also an issue where fantasy fiction can’t get away from this idea of fantasy “races” with “cool powers”. It adds this additional layer of representation that needs to happen when it’s already difficult to make real human cultures and groups feel represented in a game without infinite NPCs or world-building. Humans tend to be one or two cultures and the other “races” get coded as others. Most games would be better off without including the unquestioned trope of “fantasy races” (yes, D&D included) unless they actually built their setting and game around the idea (which most have not).