Mapnerd has provided several questions you should ponder & evaluate.
Some thoughts, based on my experience. 1st & foremost, figure out what you need based on Mapnerd's post. This is really an important part of the decision making process. Take into consideration your level of technical expertise with regards to networks, specifically how the devices in your RV (your LAN) will communicate with each other (how they connect).
I would encourage you to go to the Mobile Internet Resource Center & read what they have to say about 5G cellular service & associated 5G hardware; specifically they availability of the Qualcom X65 chip & what it will bring to the 5G cellular party. The latest & greatest technology is not referred to 'bleeding edge' without reason.
If you determine your internet needs are such that it warrants the purchase of a higher end device, I think you will like what Peplink has to offer. However, to the best of my knowledge, very few of the Pelink 5G products are currently certified for use on Verizon data only plans. There is a difference in 'it should work & being certified to work'. Take some time to view the Peplink website for product specs & look at the issues/solutions offered up on the forum.
Be advised, Peplink's 1st level support is provided by the entity from which you make your purchase. Some do a better job than others. I have purchased several pieces of equipment from Mobile Must Have. Their shipping is very quick (assuming they have the product in stock). Unfortunately, their level of support after the sale has deteriorated significantly since my 1st purchase in May, 2020. All 1st level support now appears to be accomplished via email, and, it's very difficult to now talk to a person. Anything beyond basic set up seems to be an issue they are either unwilling, or, unable to deal with. Consequently, I can not suggest buying from them.
With regards to antennas. Prior to purchasing a supplemental antenna, I would determine if the supplied antennas are adequate for your RV travels. I have yet to install my outside antenna as the supplied paddle antennas have proven to very adequate.
For what it's worth, I struggled with the purchase decision between a Peplink Max Transit DUO CAT-12 device & a Peplink Max Transit CAT-18. Based on my needs, the price differential in the initial purchase price, the yearly subscription fee for PrimeCare & potential expense for 4 data SIMs vs 2,, did not justify the purchase of the more expensive Max Transit Duo. Your mileage may vary & others may view this differently.
Information on cellular provider data only plans changes very frequently. I would encourage you to obtain data only plans that are suitable for what ever device you decide upon. You may be able to get by on the 'cheap', but then again, it may not work. I personally would stay with data only plans from AT&T, Verizon & T-Mobile in that order. This can be a very trying exercise, or, it can be pulled off with out any difficulty. Sort of the nature of the beast. A lot of variables with cellular signals & coverage. I would suggest you have a minimum of 2 different carriers. Again, your mileage may vary depending on location.
3rd party, so called 'grandfathered unlimited data plans a..k.a GUDPs' can be of good value your data consumption is very high. The trick is finding a good one at a reasonable price. In the current environment, I would attempt to determine how much data I consume each billing cycle prior to spending big $'s on a GUDP. Multiple data only SIMs from the same or multiple carriers my be more cost effective than a GUDP. SIMSs are fairly easy to change out on the devices reference in this post. Many 3rd party resellers have a dubious reputation. The good thing though, most all are month to month.
If you are fortunate enough to be in a location with good WIFI, consider it a bonus & take advantage of it. This is easily accomplished with most Peplink devices.
Good luck & safe travels.