A PB4 is like the lowest end bass they make.
Meanwhile, the average 1500 fender usually feels about the same as the average 400 fender, and from 20 ft away probably looks about the same too (maybe sounds moderately better on it's own and the same in a mix). EBs are usually great. I call BS on the Ibanezes being better than the Carvins though, unless you just had absolutely horrible luck with them.
What it sounds more like though is you're just looking for something very particular that the carvins weren't designed to provide. I've owned and played lots of carvin stuff over the last 25 years (most recent that I played used in a store was a vader 4 bass that killed). Nothing "cheap toy" about any of it, including the Bolt T that I bought used 20 years ago for $265 (basically got it like new, and would have been about $700-800 at the time).
But bolt on necks are not really their speciality. They do way more neck-through stuff (like my gorgeous LB76 from the first few years they were making them). Now, Ibanez 6 strings mostly look literally like cheap toys until you spend 1000 or more. Fender makes precisely zero of them (and when they did they were also not great looking). EB makes ONE which is surely a fine instrument but is ugly as sin. Oh, and it costs, what? 2500 or so? The Carvin though is a gorgeous natural quilted maple (with matching headstock), ebony fingerboard, no logo, and no inlays. Matte black hardware. Just classy and understated in a way that ibanez could never wish to emulate on anything but their highest end basses (which are probably still made in indonesia or somewhere yet cost a zillion dollars anyway for no apparent reason). Oh, and it sounds great and it plays great and was about $700 with HSC in like new condition. I also had a tele thinline 12 string that was maybe even nicer than the bass. I only sold that because I needed the money at the time. Figured walnut top, mahogany body and neck, birdseye maple fingerboard. 2 coil tapping humbuckers plus a piezo. Oh and it cost me like $1150 brand new with a case and would absolutely annihilate ANY production 12 string you'd care to put up against it costing 2-3x more. So forgive me if I'm skeptical of your "oh my $200 chinese ibanez is built better". I go to GC and out of their NEW basses, I'd have to play like 20+ ibanezes to find 1 that was even playable at all.
I don't know what to tell you, but your experience is absolutely an anomaly. Most people who have actually played them (not the typical internet "read about a guy who read about a guy..." stories) think they are very well built, even if they don't actually "like" the instrument for whatever reason. So that is not a common criticism of them.