When you say "4G proxies", are these devices that route their traffic over 4G connections via the mobile network? So you are using the IP ranges of telecommunications companies rather than clouds?
Also, how do you protect against customers doing illegal things with the IP's that are assigned to your business?
We have some domains blacklisted and periodically monitor logs for websites which our customers scrape but so far not a single case of illegal scraping.
We've also decided to go with a small $2 purchase instead of free trial account with no credit card required. If someone contacts us with their use case and request for a free test account, we're happy to create one for them but it has to go through us. This way we're not a good choice for people willing to do illegal stuff with our API.