Is it correct that the new Matrix builds for Wetek Play 2 will not support the internal tuner?
Yes correct. There are out-of-tree but should be usable demod and tuner drivers, but a V4L2 demux driver (which binds everything together) needs to be written and so far nobody has stepped up to do the job. Availink (who create the demod) were thinking about it at one point, but they've been quiet since last summer so .. no idea.