Welcome. Regarding food, people have different takes on how to best feed a flowerhorn, I fall into the "only pellets" camp (and for sure would never feed chicken or beef heart). Also Humpy Head and Ever Red are ok as FH foods go, but if you can't get more primo stuff like NLS, Northfin, Excalibur, etc. then I'd consider Hikari (e.g. Bio Gold+, Red Parrot+ and Cichlid gold). They're not perfect insofar as ingredient list but a step above Humpy & ER imo.
If you haven't already seen it I recently posted a good video about Flowerhorn keeping -- starting from about 14:40 the guy talks a lot about feeding only pellets, but of course do what you feel is best for your fish. And kudos, getting into the habit of daily siphoning will help your FH to feel and show its best.
Check out that video here, it's long but worth the time:
https://www.monsterfishkeepers.com/forums/threads/very-informative-flowerhorn-video.722324/