Thank you for your advice my friend, I feel like it should be so much easier to do that with the pillow thing(I am not sure what is called) when bespoke tailors iron all the curves on suits. Maybe I will bring it to my tailor and let him try that. Like you said, there is a strip underneath around the shoulder seam, it is hard for me to DIY at home.
And this suit actually didn't cost me that much, got it for less than 500 CAD, full canvassed (surprisingly), very nice material and structure. Pretty good deal if it fits me better. I do own another Lardini blazer and I really like it. I feel like Lardini is a brand that people don't know that much, they produce garments for many big names. Absolutely worth the price when they discounted for like 70 or even 80% off.
Thanks for your info.