Peron made an hour-long video about how much Armored vehicles (outside of tanks) and artillery Russia still has:
The short answer is, not much in any decent condition anymore.
BMDs are pretty much tapped out completely
For the BMPs, about 40% are already lost or pressed into service, another third are in a very bad shape and only about 28% of the pre-war stocks are still usable in some ways, of which only about half are in a decent condition. Now consider that Russia currently loses about 400-500 of these each month, and it's clear that by summer Russia will be severely supply constrained with their IFV.
MT-LB are pretty much all in use, while the MT-LBu only has about 500 left in any useful condition. However, it's very possible that most of the usage right now is not directly on the front line, but to tow artillery pieces, as Russia hasn't lost nearly enough MT-LB to account for the severe drop in storage numbers.
Now to the BTR:
- BTR-50 are all in use or destroyed
- BTR-80/82a are mostly used up with just about 75 left in storage, though the latter is still in production
- What's still in reserve are mostly BTR-60 and BTR-70, of which about 500 are still left, though they are vastly inferior to the BTR-82, with much thinner armor and very light firepower.
As for Self-Propelled Artillery guns, Russia still has quite a lot, especially the 2S1 - but that one used 122mm rounds, which are in short supply and generally weaker than 152mm or gigger guns. The bigger guns btw are mostly used up by now with only few in reserve, though there' still a decent number of 152mm SPG left.
However, Russia lost a shit-ton of towed artillery, and most of them not even by enemy fire. No, their main enemy is barrel wear, and Russia simply can't keep up with the production of replacement barrels. And it's not just a few: Before the war, there were 2900 towed mortars pieces visible on satellite imagery. Now, the total count is a whopping 0. So no wonder the MT-LB got used so much as artillery tractors, as they burned through their entire towed mortar stocks within 2 years, and the other artillery pieces are slowly following suit, the newer the gun, the less they have left of them. Funnily enough, the number of WW2 era D-1 has actually gone up instead of down as Russia seemingly has found some more in their storage buildings.
In short, more than half of the artillery pieces left are now older than Putin himself. They should still last for the entire next year, but beyond that they will be left with mostly just WW2-era guns and what they have left in terms of SPGs.
To summarise, Russia is increasingly burning through their reserves of men and material, and by mid-2025 these reserves start to run out. If Ukraine can last through the entire next year, then they will face an increasingly depleted Russian force with a serious lack or armored vehicles and artillery pieces with an increasing chance of them having a "To Berlin" marking on their barrel, way too short ranges and a lack of compatible ammunition, so they're easy pickings for loitering ammunitions or drones.
This will also be increasingly bad on Russia itself going forward, as the less they have in storage, the worse their negotiating position will become. And after the war, they will be so depleted that they will need to continue produce en masse just to replace the worst losses.