Both TTA and ALAC audio formats feature lossless compression, which means they are actually ideal for conversion and in this case no loss of quality will occur. Whilst TTA format is supported in many tools, the support for ALAC format is not that common which severely limits the potential amount of eligible audio converters.
It might be worth checking out ffmpeg as it might offer a library that can be used both to decode or encode ALAC format.
It's also worth mentioning that ALAC coded audio files are often found in .m4a or .caf containers, so checking out conversions to these formats might lead better results for file converters. Also it is possible to upload audio content to Apple Music and create ALAC files from these.
Updated: July 20, 2023