I think you are comparing apples to oranges. A cell phone booster amplifies signal (ie...the weboost) and the MOFI 5500 looks like a router to me (ie...distributes the signal to devices on the network). I did not read all the specs so perhaps there is a "booster" built in.
What I have done that works well and is cheap is to get the best booster you can afford (ie..the weboost drive reach is nice). Also get the longer range antenna for the exterior of your vehicle to use at least when you are parked.
Then you can start off with (2) used refurbished hotspots from E-Bay. One that runs on GSM networks (AT&T, T-mobile, etc...) and one that runs on CDMA (Verizon). If you buy "factory unlocked" or network specific units all you need is to go get a pre-paid sim card and pop it in the hotspot and you should be good to go.
Even though the hotspot is just a data point, it will still be assigned a phone number. What you then can do is log into your user portal (ie...Verizon) and then there is a user interface to setup your booster and apply which phone number you want to be allocated to the booster. Simply do that and then you will be effectively boosting the signal on a hotspot which you can then use to connect all your devices to. You should be then able to use wi-fi phone calling as well.
For GSM this is the best one -- https://ebay.to/3yB3zlt
For CDMA this one is solid -- https://ebay.to/2VGiPP8
99% of the time I get better signal via CDMA. If you want an ultra simple solution just add a hotspot to your actual phone plan (if you use Verizon) and then you already have a user portal with verizon to setup the Wilson booster with. I think it is $10 per month if you bring your own device (buy a used unlocked one from eBay).
Once it is setup, you can access it in the portal and there is just a dropdown to select which phone number you want to boost. Sometimes if I have an important phone call I will switch the boost from hotspot to my cell phone so that I do not have to rely on the wifi from the hotspot to take the call....I can just use the cell service directly.
So in a nutshell....buy the Weboost ---> boost your hotspot signal ---> connect devices to the hotspot.
If that does not work there are a number of other options that start to get $$$. I would start cheap and work your way up as you learn what you need.