My computer has i7, 32gb ram, 512gb ssd, and i still wish lightroom was faster. But honestly, the 4K screens make all the difference. I would recommend that you get at the very minimum, a 27" 1440p screen for a good lightroom experience. Thankfully you can find a lot of good deals on 27-28" 1440 and 4k screens nowadays. That would be a better bargain than buying another laptop. Then if you have any money left, you can look into upgrading parts of the laptop.
if you have a PC that fast and LR is still not fast enough, it's probably not a hardware issue but software related.
I have an i7 laptop that LR runs very nice on. I have a self-built i5 desktop that is pretty beasty and I reinstalled windows and LR on it and it was nice and fast. After a month it became unbearable. LR is so finicky with software issues, the adobe forums are littered with complaints about powerful rigs struggling with LR. I've just been too lazy to reinstall windows on the desktop since the laptop works so well but I know it will work fine again - the question is for how long?
Try disabling graphics acceleration if you're having problems. It's bugged for certain hardware and slows things down like crazy. I used to make a stroke with the spot brush or spot removal tool and the stroke wouldn't appear til way after I stroked. After disabling graphics acceleration, the actions are pretty much real time now. This has been a bug for years, and Adobe still hadn't fixed it.