Very close to the hotel there are many parks and squares where you can take a walk or just read a book.
Interesting places:
Italian garden, Liteiny pr.57 http://history-gatchina.ru/spb/liteiny1.htm
Summer Garden, Kutuzov Embankment, 2 https://www.spb-guide.ru/page_17872.htm
Tauride Garden, Tavricheskaya St. – Kirochnaya St. https://www.spb-guide.ru/page_21582.htm
And a few dozen more options for walking: https://www.spb-guide.ru/page_541.htm