My Car's registration expired and I am having trouble renewing it, it should be fine if I am not driving the car though, right?

You are ok as long as you do not park or drive the car on public streets

No. It many states, it's illegal to own a car with expired registration, even if you don't drive it. In some states, you will have to pay hundred of dollars extra when you are going to drive it again. In some places, it can be towed away from wherever you park it.

Most states have you sign a statement that you didn't receive any tickets or drive it while it wasn't registered to avoid a penalty fee for being late.

Your location matters with this. In most states of the US if a vehicle is parked on public streets it has to have current and valid registration and inspection. It's legal to have a vehicle that doesn't have current and valid registration and inspection as long as it's off the road on private property like in a driveway or parking lot or in a garage (parking lots are private property, not public).

You may have to pay an additional fine when you go to reactivate the registration. To avoid this, you can file a certificate of non operation now.

True only illegal if on public roads. Just sign a certificate of non operation to register with no fines.

My registration expired in May, and I just got the sticker in February, due to not being able to pass the smog check. I got two tickets (one was for $50, one was originally for $25, but was reduced to $10 with proof of registration), plus I was pulled over a bunch of times by the cops. I explained my situation, they ran my license to make sure I was OK, and let me go. So yes, as long as you are not driving anywhere, and not parked on the street, you should be fine.

Registration only happens ONCE, when you buy the car. Not every year. However, car insurance is renewed whenever it expires. I buy mine for a year, so for me once a year. My insurance is linked to the license plate. When the insurance has expired, your car better be PARKED IN YOUR YARD(not on the road in front of your house)as the road is public lands and what the cops and TOWTRUCKS PATROL to snag uninsured vehicles and take them to IMPOUND(which is a very expensive parking lot)
You do not want to end up in the IMPOUND LOT, so the car must be on your property inside the fence. Outside the fence belongs to the city.

. While the car is not insured, it cannot be driven ANYWHERE. If you want to reinsure the vehicle you go down to the insurance company by FOOT MOBILE and take the insurance papers and the registration papers with you and hand it to them and they update the insurance on your vehicle. They may also want your old license plates. I don't know. In my area the license plate is good for 5 years and they give me a sticker I put on the back license plate showing I got new insurance. Now the car can be parked on the road...or driven.
. But, I do not know what $hithole country you live in but generally those are the rules. Insurance is fairly the same everywhere in their procedures.