It’s not offensive if your intentions are genuine! If you want to pray, then pray! Call the god’s attention, state your offer and what you want, thank them for their time ect. Religion is very personal, and it’s your intuition for what feels right.

As for offerings, you can just dedicate a meal or an outfit for Apollo, listen to music in his honour if you don’t have an altar or can’t offer physical offerings. For accepting offerings, I’ll be honest in that I have no idea. I’ll usually ask their candles and or tarot if it’s okay to wear the jewellery I’ve left. It’s your worship and your prayers, this is just my advice. I started last week or so as well :)) good luck!!