Hello Adityvarma,
Thank you for posting your question. We see you want to know if your iPhone and Apple Watch are compatible with a specific carrier. We're glad to see if we can provide you with some information to get you started.
The Apple Watch model A2353 is the North America model as shown here: Identify your Apple Watch. Regarding your iPhone, this link has some detail that may be useful: Identify your iPhone model
Year introduced: 2020
Capacity: 64, 128, 256 GB
Colors: Black, white, (PRODUCT)RED, green, blue
Model numbers: A2172 (United States), A2402 (Canada, Japan), A2404 (China Mainland, Hong Kong, Macao), A2403 (other countries and regions)"
Based on the above, the model A2403 that you mentioned is manufactured for "other countries and regions." You'll find details about regional carrier compatibility here: iPhone - Supported 5G and LTE networks
For any questions about the specifics of compatibility, that's when we recommend that you contact the carrier that you wish to use directly to look into it further. We hope this helps!
Kind regards.