COuld be anything at that stage, they're usually white because they haven't developed thier outer membrane shells. But it could be anything.
Termites maybe? I have a bug book so post a close up and I'll get on trying to ID it for you.
Otherwise, use pesticides as a last resort.

Know anyone who smokes? Take cigarette butts( 15 or so) or three fresh cigarettes and break them up and soak them in a couple gallons of water( in the sun for a couple days)
then, pour into the earth.
But before you pour the nicotine, pour gallons of water with 5 or so drops of dishwasher soap into the soil and let it sit.

The soap will break the membranes and kill the eggs/younglings, and the nicotine will finish the job. ( This method is safe and organic.

Nicotene, in any form, is no longer recognized by any one as an acceptable pesticide.
The single best thing you can do is totally replace the potting soil you currently have with some other potting soil. Clean the plants roots of all the old soil and look closely to see if any of these larva may have bored into the roots.

They might be springtails but I don't think those would cause the other symptoms you describe. You can look at the Vermicomposting Formum or www.bugpeople.com to see if those are the bugs you have. I have what I am almost sure are springtails all over the place now, they come and go and I think I got them from a friend's compost and they are in my worm bin, but when you read further you can see if that's them. Let us know!

Can someone please tell me why nicotine is no longer accepted?

that is only one persons opinion but be forewarned it is a broad spectrum killer. so be sure they are not baby earthworms or something beneficial. some here think they speak for everyone.

ask him to see pics of his garden, ha!!!

This is not simply one persons opinion, it is a generally accepted opinion of many organic growers because of the known carcinogenic properties of nicotine. Nicotine is a broad spectrum poison also and for that reason alone should not be used but that known carcinogenic property should be enough to stop anyone from using it.
Arsenic, Paris Green, used to be a common garden pesticde that not many people use today for many of the same reasons.

certainly it is...yours.
"no longer recognized by any one as an acceptable pesticide. "

you failed to mention that many still use nictone effectively and there are many things much worse. some know only 1way to garden &think everyone should garden their way or noway. i be waitin for the book

I too have a white bugs In the soil and also a white translucent mite on all my avocado seedlings that im growing in water.you can see all the mites by eye but not very good. Under magnifying glass you can see more detail. I have some pictures of 3 x magnification.

I have the exact same problem in my avocado saplings top layer of soil. They don't appear to be going any deeper into the dirt than the first inch or . I've never grown an avocado plant before and don't know how to get rid of them. Found a article that said cinnamon would kill them on contact but it didn't work. They've exploded now and it's so gross I don't want to go near it. My poor plant 🤢🥺