A safest place could have been in the direction of Ignalina, the area has low density population both in Belarus, Lithuania and Latvia.
And because the Lithuanians did build a NPP in that position in precedence, they would have lost one of the main point they are complaining about: proximity to the capital
In our non-democratic country all decisions are made by single person and you know his name. The idea of selling electricity to Baltics was imposed by Russia to him. Russia gives loan and builds NPP, and Belarus makes money. Who'd say no to this, right?
Now, when Lithuania makes everything it can to ban transferring electricity from Belarusian NPP into EU, our government has a painful headache. They really don't know how to use this electricity inside Belarus. They also need to build new reserve capacity for NPP.
P.S. 1-st NPP in Belarus/BSSSR were being constructed ~ in 35km (22 miles) from Minsk (capital). But it was cancelled after Chernobyl explosion and converted into gas-fired power plant.
P.P.S Less than mont ago our minister of energy were talking about 2nd and 3rd NPP.
Belarus previously had 99% of its electricity produced by thermal plants. The new NPP will produce 30% of the power in Belarus and seriously reduce greenhouse gas emissions.
See: https://twitter.com/RosatomGlobal/status/1323580827377258507
Also, where do you suggest building a hydro power plant, given that the difference between the highest and the lowest point in the country is about 200 m?