Up until a few weeks ago I was running my own private SearXNG instance and it's not just you, even I noticed on my OWN instance that it had progressively gotten worse. Initially it was great so I just left it be but then the performance and results just became horrible. It was hit or miss if the thing would even load or not when other instances on my server like my akkoma, piefed, redlib, forgejo, etc all ran smooth as silk.
Eventually I ditched SearXNG and switched to 4get which much better and faster results. thing never goes down and the search results have been fantastic.
I tried it, paid for it, cancelled it. I tested it with the same queries with ddg, startpage, brave, and qwant via 4get. The results were essentially the same. Kagi did provide more context in the description of the results but it wasn't anything I would pay a premium for. the majority of features I just didn't use, the assistant and fastgpt were a waste, lenses were fine and having fediverse on by default is neat but nothing I'd call home about.
If it were cheaper sure, I might stick with it but I can't justify the price to anyone wanting to use a search engine. $5 for 300 searches a month is a joke. I also don't like the fact that if you want to pay with something other than a credit card (paypal, venmo, etc) you get charged extra cause Kagi doesn't want to eat the fees. Also there's zero option to opt out of paying for the "AI" features, you can turn them off sure...but you're still going to pay for them.
If your internet usage consists of constant searching and LLM use for searching then sure, you're going to be paying $10+ a month and be happy with it. But there was nothing Kagi offered that knocked my socks off. if anything, felt like I was getting scammed.