I am starting like your self and sharing what I have gathered in the process. Many experienced forum members further help you after you shortlist some components.
First investment will be AVR. Considering shortage of supply, prices are skyrocketing.
For AVR, following are the option I shortlisted for myself for atmos setup
1. Denon 1600/2700
2. Yamaha V6A/A2A
3. Marantz 1610
AVR will cost you 60 to 75k with atmos. AVR can be bought based on feedback & reviews.
For speakers, its better you audition them. If you decide to purchase AVR first, you can carry your AVR with you at audition to see how speaker sound with your AVR
If you going to buy Sub, buy bookshelf instead of floor standing.
@DB1989 highly recommend Mission QX2 as bookshelf. You can choose center from same series as many advocate to have LCR from same brand series to match the tone.
For surround you can consider Polk Owm3, S10/15. I have purchased Owm3 for myself and yet to be arrive. I have auditioned S10 as surround and couldn't found any fault.
For atmos/ceiling speaker, consider space availability before finalizing. POLK RCi series, Owm3 can be installed as atmos.
Regarding Taga Harmoney, there are many forum members who are using them and happy with them. You are getting complete package for the price for bookshelf i have mentioned above. So your getting what are you paying for. You may get itch to upgrade in some time. That's why its always recommended to go for audition.