1brunoj

concern is buying a transmitter that will work on multiple gliders/planes. Further glider that I want designates transmitters that are not available until 4/1/21

Do I have to select glider/plane to match transmitter that I have.

Would a SPMR8105 DX8e 8-Channel DSMX Transmitter work on plane that designates
SPMR6750 DX6 6-Channel DSMX Transmitter Gen 3

ditto would a DX6e 6-Channel DSMX Transmitter work for designated SPMR6750 DX6 6-Channel DSMX Transmitter Gen 3

Can receiver (whatever that is) be changed in plane to match transmitter?

Panther

Answers are all yes.
The receivers can be bound to match the transmitter and changed to another Transmitter if so desired.

The glider or plane doesn't matter. It is the receiver that goes in it that matters.

Wildflyer

Are they recommending one of the new Spektrum NX series?

solentlife

Given the Multi-Protocol radios out there now - plus the module radios ......

The need to stick to same brand Rx / Tx is fast losing its reqt.

1brunoj

can't just select any spektrum transmitter, a lot not available until 4/21

quorneng

1brunoj
If a plane receiver is specified for DSMX then it should work with any DSMX transmitter provided it has a sufficient number of channels. The plane's specification will show haw many channels are required but it is rarely more than 6 for a beginner plane.
As the transmitter is relatively expensive and last a long time (compared to planes!) it is advisable to purchase one with more channels than is immediately required to allow for a something more complex to be flown in the future.