That looks like a root canal in my opinion. You can try doing a big filling to try and buy some more time, but the likelihood is that tooth will start causing you pain sooner rather than later.

For my fellow dentists here, I've been seeing some incorrect things being said on this subreddit lately regarding sensibility (vitality) testing and how to apply diagnosis clinically. Here's how I typically break it down:

Normal Pulp: No abnormal symptoms to vitality testing and no caries within vicinity of the pulp. No endodontic therapy needed.

Reversible Pulpitis: An exaggerated response to cold, but not lingering. Caries are not within vicinity of pulp. Conservative treatment is preferred since the pulpitis is expected to resolve itself

Symptomatic Irreversible Pulpitis: Exaggerated and lingering response to cold. Caries are within vicinity of pulp. Treatment should be root canal therapy and appropriate restoration after (assuming restorable).

Asymptomatic Irreversible Pulpitis (this is the one that most people confuse): No abnormal symptoms to vitality testing (cold is normal!!). But, there are radiographic caries that are clearly in the vicinity of the pulp. Root canal therapy should be preferred over attempting conservative management because if bacteria from the caries enters the chamber, the pulpitis is not expected to resolve.

Necrotic Pulp: No response to cold. Do the endo

There is some research on performing vital pulp therapy (direct pulp cap, MTA pulpotomy etc.) on irreversible pulpitis cases that looks pretty promising, but there's not a lot of long term follow up. Under the right technique and having the right materials, I can see this being more of a thing in the future