IMO whether / to what extent you can replace LR and PS depends on how you use them, and how close a pair of replacements you need. For someone looking for a pixel editor who doesn't need quite everything PS offers and doesn't need to do raw conversions with the pixel editor, the new free Canva Affinity 3 is probably a pretty good substitute, albeit with something of a learning curve. Maybe you'd find the free / open-source Darktable an adequate replacement for LR as a DAM and raw converter. If you don't really need the DAM, then the free / open-source RawTherapee (which has a substantial learning curve) might be an adequate raw converter for you. If you print yourself and you use Windows, then you probably need to add the free Epson Print Layout (if you have an Epson printer) or Canon Professional Print & Layout or Canon Print Studio Pro (if you have one of the supported Canon printers). So that at least mostly replaces LR and PS for free. That said--and I say this as someone who has pretty much abandoned Adobe for photo software--if you want something that will be over time substantially less expensive than Adobe, then you probably have to accept tools that are 'less than'. I'm not claiming that my suggestions are as good or as powerful or as capable as LR + PS; the question is whether they're enough for you.
Or you can get non-subscription software that's arguably about as good over all--but isn't really less expensive over the long term. Since mid-2017 I've used (and paid modestly for) Affinity Photo 1 and then Affinity Photo 2, and the new Affinity 3 appears to have all the same capabilities and more, so that might be a happy PS substitute. I used to print with LR, but now I use Qimage Ultimate, which I think is better and more powerful. I don't want and don't have a DAM. Then the real issue is raw converters. I think DxO PhotoLab Elite is the best (and I also license the optional DxO ViewPoint and FilmPack). But whether you license and pay to periodically update PhotoLab etc., or the same with the other IMO 'best quality' raw converter, Capture One, over time I doubt how much money you'd typically save over Adobe. Yes, you can get a perpetual DxO license and use it for many years, but after a year or two new cameras and lenses won't be supported. Overall I like my tools better than the Adobe alternatives, and I think overall they're about equally capable (better in some ways, worse in others). But I don't think they're clearly less expensive.