The # of good defenders on the team already is not relevant, nor the number with "well-rounded profiles". What matters is the total value of all the players on the team in terms of creating and preventing runs. Soto is a 5-6 WAR player, his value is 5-6 wins above a replacement player, it doesn't really matter how it breaks down. If he DH'ing for the Cubs, which he will most of the time, his value/WAR drops because it's easier to replace a DH than any other position. According to fangraphs, a LF (or RF) is penalized -7.5 runs in value, and a DH is worth -17.5 runs: https://blogs.fangraphs.com/explaining-win-values-part-three/
The issue with the Cubs isn't spending and payroll, they spent enough last year to win and will again this year, their issue in 2023 was efficiency. They desperately need more surplus and efficiency. They clearly overspent on Mancini and Smyly who were terrible, Barnhart also, Fulmer/Boxberger plus Rowan Wick/Adrian Sampson were busts, Taillon underperformed pretty badly in his first year, Rios and Hosmer were crap, Stroman arguably under-performed, and Heyward and Bote provided nothing for the millions they made. That's almost half the payroll in either under-performance or total waste.
They got surplus from Nico, Steele, Happ, Bellinger, plus a few pen guys and less significant players (Assad, Morel, Tauchman etc), but the pen was useless at holding leads half the year because they didn't spent enough on late-inning depth. The difference between 2016 and 2023 wasn't payroll, it was efficiency and surplus. The whole point of being a GM is squeezing as many wins out of every million spent as possible.
I'm not at all against a Soto trade, even on a 1-year, but trading our DH (who can also play middle INF and potentially 3B) who was 3rd on the team in wRC+ last year for a much better DH plus the cost of 33m is not the impact move I think some people think it is. Soto at 33m arguably still has some surplus, it's a good acquisition. But Soto on a 1-year is a win-now move so we need as much MLB talent and surplus as possible in 2024, so as i've said they should trade a prospect that won't contribute in 2024, like Triantos or Arias, or Rojas etc., not trading away our 3rd best hitter (#2 now that Bellinger is FA) who makes league minimum.