That sounds like a phishing scam waiting to happen. You’re funneling your data through some random third-party website to “anonymously” view something. Best case scenario, they’re just plastering it with malware-infested ads. Worst case, they’re harvesting credentials or browser data.
And you seriously think Instagram can’t detect this? Using third-party apps to scrape their site is a great way to get your own account flagged or banned.
Before you ask if it’s “reliable,” you should be asking for a privacy policy and a security audit. Source on this thing being safe at all?