I am confident you are already aware of this, but in case you are not: if you find there are issues with the MSFS default navdata and planner (and that navdata is coming from an Airbus company called Navblue, and the planner is made by Asobo of course) that you really can’t live with and it’s being a deal-breaker for you, I highly suggest you make a report of this in the #self-service section where people can upvote the problem to bring it to the MSFS developers’ attention.
I say this because you first and foremost are a customer of MSFS, and before you bought the sim, the products such as realistic, actual real-world navdata and Charts+ were advertised to you in plain English. If the products are not up to par, the developers need to be made aware of this, instead of you as a customer going out and spending money on another product just to solve the issue.
You as a customer of MSFS have paid Microsoft and Asobo for real world navdata and Charts+. If you are finding them so unusable that you now feel like going out and paying for another navdata and charts product made by another company, that’s a big problem and needs to be addressed first.