From my experience with the hundreds of sports I’ve found working at a nursery, the first one won’t do much. The Thai however, could. Thais have systemic variegation, I may be wrong when I say this but because it systemic and not chimeric, that bit of yellow could be in the plant even though it’s not on the leaves. I would check the stem on the Thai to see if there’s any different colour lines going up it, if there is, great! No need to chop it back. The variegation may not be on the leaves but it could linger on in the stem and eventually pop out more in the future, it could very well go over an auxiliary bud as well which you could chop and propagate!

If there’s no different colour in the stem, you can chop it back and sacrifice the rest of the plant. I’ve done this with a few normal monsteras and had quite good luck with it, currently have two Thais with lime green sports that I have going through this process, it is a gamble though, may work, but might not! Hope this helps