Beijing and Tianjin also pay social security.

This is impossible ... it is impossible for social security in cities all over the country to be completely merged automatically ... because the social security payment bases in different places are completely different ... some cities have many social security personnel, while others have few social security personnel ... and it also involves the interests of people in each city.

Social security in different places will also be transferred to other places ... the local social security department will not agree.

At present, it can only be said that after you go to Beijing to work and pay social security, you can apply to transfer your pension account and payment period back to Tianjin Social Security (previously only transferred to individual pension account). The money in the overall account should stay in the local area for all people to share and contribute)

So it doesn't matter. You'd better go back to Tianjin to work.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.