Psychological Triggers Not Hitting?

Hey everyone, hope you're all having a productive week!

I'm hitting a bit of a wall with my SaaS (it's a project management tool for small teams) and would love some input from the community. We've got decent traffic and sign-ups for the free tier, but our conversion rate to paid plans is stubbornly low, hovering around 1.5-2%. It feels like we're leaving a lot on the table.

I've been diving deep into marketing psychology, thinking this is the key to unlocking better conversion numbers, but so far, my efforts haven't really moved the needle.

I've tried implementing several common psychological triggers based on best practices I've read about:

• For scarcity, we tested 'Only 5 spots left at this price!' on a landing page for an annual plan. Result: no significant change, maybe even a slight dip.
• For social proof, we added 'Join 10,000+ happy teams!' and displayed a rotating carousel of client logos. While logos are good for credibility, the conversion uplift from explicitly stating the number of users was negligible in our A/B tests.
• Urgency was another big one. We ran a 'Limited-time offer: 20% off for the next 48 hours!' campaign. People seemed to ignore the countdown timer, and we saw no real spike in purchases before it expired.
• Even reciprocity, where we offered a really in-depth, free project management template pack in exchange for an email, didn't seem to make those leads convert any better down the line. It felt like they just took the freebie and bounced.

It's frustrating because these principles are supposed to be foundational for effective Conversion Rate Optimization, yet they're just not clicking for us. Sometimes, the A/B test results are so flat they almost make me think I'm doing something wrong, or worse, making things worse.

Here's a snippet from one of our recent A/B test results for the 'Urgency' trigger. As you can see, the confidence interval overlaps significantly, indicating no real winner:

A/B Test Report: Q3_Urgency_PricingPage
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Test Duration: 2023-09-01 to 2023-09-15
Hypothesis: Adding a 48-hour countdown timer will increase paid plan conversions.

Variant A (Control): Standard Pricing Page
  Conversions: 152
  Visitors: 8100
  Conversion Rate: 1.88% (CI: 1.70% - 2.06%)

Variant B (Urgency Trigger): Pricing Page + 48hr Countdown
  Conversions: 148
  Visitors: 8050
  Conversion Rate: 1.84% (CI: 1.66% - 2.02%)

Statistical Significance (p-value): 0.68 (Not significant)
Lift: -2.13% (Confidence Interval: -15.4% to +11.1%)

Conclusion: No statistically significant uplift observed. Variant B did not outperform Variant A.

So, my main questions to the experts here are:

• Am I completely misapplying these psychological principles, or is there a nuance I'm missing?
• Does the specific context of a SaaS product (especially B2B-ish) make certain triggers less effective or require a different approach?
• Is it possible our audience is just desensitized to these common tactics, and we need to go deeper?
• Are there any advanced marketing psychology frameworks or less obvious triggers you've found incredibly effective for SaaS CRO that aren't just the usual scarcity/urgency playbook?
• I'm particularly interested in how to build genuine trust and perceived value using psychology, rather than just trying to rush a sale.

Any insights, personal experiences, or recommended resources would be hugely appreciated. I'm really eager to learn from anyone who's successfully navigated this challenge. Thanks in advance!