I've recently had the opportunity to try out several K&F filters and for the price they are, I think the quality is excellent.
There are probably filters from other brands that are much better but the prices will also be in line with that quality and as I am only an occasional hobbyist and I don't make a living with photography, I don't see the need to invest in more expensive filters when these K&F filters give me such good results.

The UV filter doesn't seem to cause any loss of sharpness or changes in tone. It's not that I've made thousands of comparisons between photos with and without the filter, but in the basic tests I did on them when I received them I couldn't see anything unusual. For now, this filter stays fixed on the lens to protect it from scratches.

The CPL filter does its job perfectly. It has a very smooth rotation so you can adjust it to the needs of each occasion and it eliminates almost all reflections.

Both filters can be used at the same time, which makes it very convenient as you don't have to remove the UV when you want to use the CPL.

The price of the pack seems very good to me if you don't have either of the two filters yet. If you already have one of the two, it will probably be more cost effective to buy the other filter separately.