No audio when playing 1:1 Bluray when audio is DTS MA

I have a POS old 5.1 dvd in one system and while I would love to have a 7.1 that decoded everything under the sun it’s not going to happen anytime soon…my question is why won’t the blurays I have with dts masters not play audio…don’t blurays come with more audio options besides just using dts masters…A couple of 1:1  blurays I have do work im not sure if they were TRU HD or masters i need to check again…is my only hope to get a reciever that will decode dts masters?

Im not very well versed in this stuff so sorry if it’s a little incoherent

Im am using hdmi to tv and toslink optical to receiver