I am aware how polarized the american society is. There are not a lot of independents and swing voters, but the number of them is still relevant because most elections are split near 50/50.
In a 50/50 election like in Georgia, these things matter.
The other is turnout. Democrats had a good turnout 2020 because people wanted to get rid of trump. That is gone now, but the trial can let some of that live up again. At least that is my estimation of it. It is not the ONLY thing, but in tandem with IRA and some smaller stuff, it can swing some good will and enthusiasm in democrats and that will be necessary to keep the senate and, if we are very lucky, the house.
About political polling: It is complicated. Polling should always be taken with a grain of salt, but it is also pretty accurate on average- America is especially hard to poll because of its system (it is far easier to poll the popular vote than to say who wins an election that is gerrymandered), but i do believe that general polling can give a good estimate about which battleground are ahead for one side and which are very even.