I'd like to remind you that an absolute unit of Polish industry was piece by piece moved to USSR. Which I already told you about earlier IIRC including list of moved heavy industries.
Anyone claiming Soviet invested in Poland should compare the amount of German war reparations that Soviet took over that should've been paid to Poland vs the "investments" made by the USSR.
A trade agreement concluded with the Soviet Union early in 1948 had ensured the importation of investment goods to the value of £112,000,000. In general, trade with the Soviet Union had risen from 0.4 per cent in 1938 to 21.5 per cent in 1948; and trade with her and the other countries of planned economy now accounted for over a third (37.8 per cent) of [the Polish People’s Republic’s] total foreign trade
Thank you for proving my point that we were forced to "trade" with the USSR. Subservient, colonized trade. For example, the USSR forced Poland to invest in shipbuilding (that we had to loan for) with a quota of ships to be traded for, for which of course the payment was transfer rubles managed by the USSR empire in their centralized bank - forcing inter-USSR trade by the prices made by the USSR. (Btw transfer rubles were also a part of Polish financial problems after 1990, see https://pl.wikipedia.org/wiki/Afera_rublowa#%3A%7E%3Atext=Afera+rublowa+%E2%80%93+Wikipedia%2C+wolna+encyklopedia)
Anywho, by the 1980 the USSR, under prices that they enforced, Poland owed USSR 4 billion transfer roubles and was demanded to repay that in USD at the value of 7.3 billion USD.
The next most important items were several large chemical factories. Pre-war Poland had had no chemical industry
Poland was a free country since 1918. Before that it was conquered by Russia, Germany and Austria for 123 years. In the 20 years of not being a colony and exploited by those 3 countries, Poland has managed to kickstart it's own chemical industry, to be top of the class in post WW1 Europe - see example https://pl.wikipedia.org/wiki/Historia_Zak%C5%82ad%C3%B3w_Azotowych_w_Tarnowie-Mo%C5%9Bcicach
If your source claims that Poland had no chemical industry, you can use that source as a kindling.