Till now the PC has not slowed down. I just had to disable ESET Banking Protection and remove Chrome from AppGuard guarded list.
You are right partially. Maybe they are not needed when using ESET. But I keep Sandboxie just to isolate my browsers which ESET cannot do at this moment. I have AppGuard kept as a default deny protection since ESET by design is default allow.
The trend right now for us security geeks is to not engage in overkill, to avoid protection redundancy, and to avoid conflicts and slowdowns that can actually negatively affect your security.
But... I'm more like you in that I like to have 'two major muscle groups' on most computers. So (like you) I'm using capabilities that many could consider stand-alone capabilities together. So I'll run VooDoo with some AV, or MBAM Premium with an AV, or AppGuard with an AV... I have several computers that run a traditional AV with Cylance (which like MBAM premium, can be considered an AV replacement). And I often have a few more 'things' running... OSArmor, SysHardener, uBO, MBEB, WDBP.... I've got quite a few computers in my larger household, so there is a lot of mixing of different set-ups.
So I do tend toward what some here might consider overkill. But, I typically don't experience conflicts nor slowdowns. And while there is some spectrum double-covered, in each case, there are some specific areas of specialty that are being addressed.
But... when I used to run things like AppGuard, NoScript, Sandboxie, EXE Radar Pro, Aggressive uBO, some uBO filter lists, DefenseWall (going back in time) and other capabilities that had me spending too much time trying to figure out why so many websites or updates didn't work properly, I did get 'security fatigue' after a while. I don't really tolerate that too much anymore.