If you want to search for two or more words that occur on multiple lines you can use ripgrep's option --multiline-dotall, in addition to to provide -U/--multiline. You also need to search for foo before bar and bar before foo using the | operator:
rg -lU --multiline-dotall 'foo.*bar|bar.*foo' .
For any number of words you'll need to | all permutations of those words. For that I use a small python script (which I called rga) which searches in
the current directory (and downwards), for files that contain all arguments given on the commandline:
#! /opt/util/py310/bin/python
import sys
import subprocess
from itertools import permutations
rgarg = '|'.join(('.*'.join(x) for x in permutations(sys.argv[1:])))
cmd = ['rg', '-lU', '--multiline-dotall', rgarg, '.']
# print(' '.join(cmd))
proc = subprocess.run(cmd, capture_output=True)
sys.stdout.write(proc.stdout.decode('utf-8'))
I have searched successfully with six arguments, above that the commandline becomes to long. There are probably ways around that by saving the argument to a file and adding -f file_name, but I never needed/investigated that.