Since there are a ton a unanswered questions about the new S10 on Boost Mobile, I took it upon myself to make one google search and found the answer.
Quoted directly from Sprint
"Galaxy S10e Coming to Boost Mobile
Samsung Galaxy S10e can also be paired with no-contract plans from Boost Mobile giving consumers an additional way to save and find the best option to fit their needs. Galaxy S10e in prism white will be available for purchase beginning on March 8 in Boost Mobile stores and at www.boostmobile.com."
Only the s10e will be available on Boost Mobile. The regular s10 and s10+ will not be compatible with Boost Mobile. And, as stated in the news release, the s10e will be available on March 8th for purchase.
No where is it stated that the S10 and S10+ are not compatible only that you will be able to purchase a Boost branded S10e starting March 8th.
The same thing happened last year with the S9 being available for purchase as a Boost branded phone but S9+ was still able to be activated and used on Boost if purchased outright from Sprint or unlocked from Samsung it usually is a week after the initial launch date is all