Not sure how you tried to install it, but I managed to install it with docker a couple years back. Not sure it’s still up to date but here’s the docker-compose

version: '3.3'
services:
    cryptpad:
        environment:
            - CPAD_MAIN_DOMAIN=example.com
            - CPAD_SANDBOX_DOMAIN=sandbox.example.com
        volumes:
            - '${PWD}/data/blob:/cryptpad/blob'
            - '${PWD}/data/block:/cryptpad/block'
            - '${PWD}/customize:/cryptpad/customize'
            - '${PWD}/data/data:/cryptpad/data'
            - '${PWD}/data/files:/cryptpad/datastore'
            - '${PWD}/config.js:/cryptpad/config/config.js'
        ports:
            - '3000:3000'
            - '3001:3001'
        image: promasu/cryptpad

You can also try onlyoffice or collabora. Have also a look at this.

CryptPad is already pretty light. Any interest in debugging what’s wrong with your setup? Want to share some bullet points about the setup you tried?

Etherpad?