My renovation increased the appraised value by less than I spent, and I want to understand how that happened before I buy the next one

Bought a condo in Denver's Sloan's Lake area in early 2023 for $410k. Put about $38k into it, kitchen, primary bath, new flooring throughout, finished out a small storage room into a proper office. Comparable sales at the time of the work suggested I'd land somewhere around $465k to $475k when done. Appraised at $448k. So on paper I recovered maybe $38k of the $38k I spent, which sounds fine until you realize I had carrying costs on top and the value gain was basically zero net of that. The appraiser's comps were all pre-renovation sales in the building and one unit two blocks over that had not been updated since 2015. I don't know if that was the right call or a lazy one. What I can't figure out is whether the appraisal methodology just doesn't give full credit for condition upgrades in a condo, or whether I genuinely over-improved for the market at that price point, or whether the comps available at that moment were just a bad draw. I'm closing on my first rental in about six weeks, a single family in Lakewood, and I'm trying to get my head around this before I make the same error again. If I'm planning a value-add play and the appraisal can't see it, that changes what I'm willing to pay today.