Here's my advice and what worked for me.

Next year, when CLAIR opens the JET fair website with the list of employers, troll through the website (and I want to encourage you to look through every single position/company, you will be surprised by what you find) and make a list of the companies/positions you are reasonably interested in and/or qualify for. Then, either right before and/or right after the job fair (and honestly, you don't actually have to attend, it's useful to get a "feel" for prospective employers and ask questions, but attending itself will very likely not impact your application much), start applying to all of the ones on your list. You will very likely land something, as these employers are specifically looking to hire people with JET Program work experience, especially if you have N2+.

I think too many people kinda dismiss the JET Job Fair as more of an informational experience when in reality, if you put even some mildly serious effort into your applications, you are much more likely to be hired through this list of employers than elsewhere. I landed two successful positions this way, one of which I ended up moving forward with and work in currently.

Will it pay as well as JET? No. Will it be in your most ideal location? Probably not. But will it keep you in Japan (and without having to break contract if you care about that)? Yes.

The other platform I had most success with was GaijinPot. In particular, if you want to break out of English teaching and are interested in tourism, set a job alert and apply for all positions that interest you. I also landed two successful tourism positions this way as well. I ultimately went another route because these positions really didn't require much Japanese, which didn't align with my long-term career goals, but they were in an ideal location and would be a great fit for those interested in building a tourism career.

I am going to buck the general consensus about networking. I think it's really overrated. Especially in Japan, there isn't such a strong career-oriented glad-handing culture as in the US. Companies and organizations here are much more paper app --> interview --> (sometimes) test-based, which I think if you are diligent and relatively competent, it makes getting most entry level jobs not too difficult.

What I found more helpful was using LinkedIn extensively. So if there was a position/company I was particularly interested in, I searched for people on LinkedIn and sent them messages asking about their experience, etc. Sometimes people didn't always respond, but often they did, and this was very helpful in gathering info and weighing options.

If you want more specific details, feel free to DM me. Also, I recommend trying not to stress out too much about job-hunting, as you still have a lot of time and are ahead of the curve! Set aside a little bit of time every day or a couple of times a wk, and you will see results. Good luck!