How much defense does Russia even have at this point? They seem to be banking on their nukes to defend them.

Not much work around there and the market only decreases + most men came through obligatory service so they believe they know-how + employer DGAF if you are an ex-con or a neo-nazi + you earn in a month what you may not do in a year + shooting hardly armed brown people was pretty safe + and with mobilization there is a promise you'd be better treated, equipped and trained there if you sign contract with them. They previously hired from ex-Yugoslavia countries since there are many sympathizers and not the best economics in EU too; and Ukraine is probably the only post-CIS state they don't have a recruitment campaign in. The only limit I see is funding, and they deal in oil and food catering for government for that. I see their numbers get reported pretty conservatively while they are a big deal to actually be concerned about. Yet it took only 9 years to proclaim it as such.

If you don't want to trust Wagner (and I don't blame you) this part of the article has another relevant fact:

U.S. intelligence said in February that Wagner had at that point suffered 30,000 casualties in Ukraine, including 9,000 deaths.