>> 1. 17th January 2023 (it's equal to the "receipt date" on the top left side of the receipt form) --> So should I consider 17th January 2023 as NOA1 date?
Yes, this is also your "priority date" (PD) which they use to calculate the estimated processing time of your case and so on. But be aware that their processing time is not accurate in many cases.
>> 2. Don't know what you mean. The receipt notice actually is the I-797 form. --> I found over internet that there is "I-797" printed on the receipt notice, so just wondering, how "I-797" is not there in online receipt notice.
That's right. It's not on mine on the USCIS account version either, just on the printed (snail mail) version.