As others have said, most "big" swords eventually will out grow your tanks. Maybe 1 in your 29g, but if happy it'll take over almost the entire tank. Not much room for fish or other plants.
I think, seeing your list & pics, I may have answered you before. It doesn't change the eventual outcome...big swords, small tanks, cute crypts!
Try looking for echinodorus flame, echinodorus parvilorus, echinodorus hadi red pearl... they grow smaller for swords standards and would do good in 20 gallons.
And yes!! Sand is just fine for plants. Don't need fancy substrate. All that fancy aquarium soil goes inert after awhile and you end up needing to add liquid ferts to the tank anyways. Just skip that hassle lol
All my tanks use plain old play sand, and plants do fantastic.
My most heavily planted tank... all sand! I don't even use root tabs anymore, just stick to good liquid fertilizer.
For plants, I really recommend limnophila sessiliflora. It's beginner friendly, fluffy, bright green, and grows fast. Doesn't need much either. Would be happy with some ferts, but doesn't need anything crazy. Can see it in my tank in the middle between the lilies.
I was thinking about ripping out the two swords that are not doing too good for awhile now but I keep procrastinating. I only know of two places locally that I can get aquarium plants from and one of them I don’t trust anymore. I was thinking about trying to order online but not sure about them getting here in good condition? I keep wanting to try aquarium co-op since I order a bunch of stuff through them but it’s clear across the map?
Lots of different plant varieties and lots of ferts!
I recommend Thrive ferts if you are in America. If in Canada there's another one thats just as good which is what I use.
Looking at my local fish stores website, I have access to Several types of Anubis’s, swords, crypts. As well as Banana plants, moss balls, Java ferns, water sprite, Ludwigia, anacharis, cabomba, hornwort, hygrophilia, moneywort, myriophyllum and wisteria.
Liquid! Caps aren't really necessary, even swords can grow fine with diligent dosing on the liquid, but if you feel you may be forgetful, can get tabs for swords and such too.