I have seen no reports of anyone having problems onboarding using Ecency. If you do have any problems I would suggest reporting in Ecency Discord #issues channel so that they are brought to the attention of developers who can respond.
I included a 3speak video in a post this week using Ecency app and it displays as expected.
I loaded the video to 3speak using my Ecency video gallery in the app and was able to choose the thumbnail that I wanted displayed.
I'm happy to help and can find answers to any questions that you might have.
My entry is not just about Ecency, but about Hive in general.... A person hears about Hive, wants to set up an account and has many options to choose from. It's a lottery. I know people who wanted to create account with Leo and they were completely lost.
Today I tried it and there is indeed an improvement. The video loaded in a fairly short time and you can add a thumbnail automatically. A step forward!
Please reach out anytime you have issues. Ecency devs are always happy to hear reports of issues. It's the only way they have to know that things aren't working as expected!